2004ApJ...614L.105W

We present mapping observations of molecular lines ¹²CO (2-1), ¹²CO (3-2), ¹³CO (2-1), and ¹³CO (3-2) toward the massive star-forming region IRAS 04000+5052 that suggest kinematics consistent with cloud-cloud collision and a possible unusual abundance ratio of carbon isotopes. Together with the previous spectroscopic study that shows an extreme deficiency in heavy elements in the surrounding nebulosity–suggestive of primordial nature–we propose that the cloud material is of intergalactic origin and that the young star cluster in IRAS 04000+5052 is the consequence of triggered star formation due to the collision of a Galactic cloud with accreted intergalactic material.